Heat transfer device for tubular material

ABSTRACT

A heat transfer device for tubular material and particularly a dryer for relatively fragile material in which a drying section of the dryer has a tubular perforate member through which the material travels and with baffles located in the chamber to cause relatively high velocity air to impinge along the entire length and about the entire periphery of the tubular material passing through the tubular member and with the air being exhausted from both ends of the tubular member to minimize the effects of air flow on the tubular member to minimize the effects of air flow on the tubular material.

United States Patent [451 Apr. 4, 1972 Seedorf [54] HEAT TRANSFER DEVICE FOR TUBULAR MATERIAL [72] Inventor: Robert R. Seedori, Barrington, 111.

[73] Assignee: The Roy M. Mofiitt Company, Schiller Park, 11].

[22] Filed: Mar. 10, 1970 [21] Appl.No.: 18,214

PIVODUCT Primary Examiner-Charles Sukalo Assistant Examiner-Harry B. Ramey Attorney-Hofgren, Wegner, Allen, Stellman and McCord [57] ABSTRACT A heat transfer device for tubular material and particularly a dryer for relatively fragile material in which a drying section of the dryer has a tubular perforate member through which the material travels and with baffles located in the chamber to cause relatively high velocity air to impinge along the entire length and about the entire periphery of the tubular material passing through the tubular member and with the air being exhausted from both ends of the tubular member to minimize the effects of air flow on the tubular member to minimize the effects of air flow on the tubular material.

8 Claims, 6 Drawing Figures PATENTEDAPR 4 I972 SHEET 2 0F 3 NWN PATENTEUAPR 4 I972 SHEET 3 [IF 3 BACKGROUND OF THE INVENTION This invention pertains to a heat transfer device for tubular material and more particularly to a dryer for relatively fragile tubular material such as thin wall plastic or collagen casing which delivers high velocity air against the casing without major impact and wherein the air is balanced to keep turbulence at a minimum and obtain maximum drying efiiciency. The casing can run either vertically or horizontally through the heat transfer device.

A number of patents disclose the production of tubular collagen casing with a step in the process being drying of the casing. These are US. Pat. Nos. 2,123,653, 3,425,846 and 3,425,847. In the latter two patents only general reference is made to a dryer while in the first patent the specific construction of a dryer is disclosed wherein air is directed against the casing but without balancing of the air and delivery thereof at a high velocity around the entire periphery of the casing. The prior art known to applicant does not delivery high velocity air completely around the casing with the air being balanced to keep turbulence at a minimum and provide maximum drying efficiency and wherein each drying section is relatively short to avoid any tendency for the tubular material to prevent whipping and stretching while travelling through the dryer.

SUMMARY An object of this invention is to provide a heat transfer device for tubular material and more particularly a dryer for such material wherein such material is relatively fragile, for example, collagen casing.

Another object of the invention is to provide a heat transfer device for tubular material wherein the device has a chamber with a perforate tube disposed therein and with open ends of the tube opening outwardly of the chamber ends to permit travel of the material through the tube, an air in-let to the chamber intermediate the ends thereof for receiving high velocity air, means for distributing air in the chamber to cause air to enter through the perforate tube entirely around and along the length of the tubular material, and an air return system connected to both ends of the tube for dividing the exhaust air fiow out of the chamber.

A further object of the invention is to provide a dryer for fragile tubular material having a plurality of treatment zones through which the material travels for progressive drying thereof with each of the zones having a plurality of drying sections and wherein each section has a chamber with spaced apart end bulkheads and with a pair of laterally spaced perforate wall tubes extending between the bulkheads intermediate the top and bottom of the chamber and opening to the space beyond the bulkheads to permit travel of the tubular material therethrough, an air inlet at the bottom of the chamber intennediate the bulkheads, a bafile across the inlet to break up the path of the entering air, an air return connected to the spaces beyond the bulkheads whereby air leaves from both ends of the tube to minimize the effect of air flow on the material, and means within the chamber to cause uniform air flow through the entire periphery of the tube and along the entire length thereof to impinge drying air on the entire surface of the tubular materials in said tubes.

An additional object of the invention is to provide a dryer as defined in the preceding paragraph wherein the means for causing uniform air fiow includes a perforate plate spanning the upper part of the chamber and spaced above the tubes and with an air guiding channel extending the length of the chamber and opening toward said perforate plate and having horizontal sections with perforations whereby air entering through the inlet can pass to the tubes through the perforations in said horizontal sections and also pass upwardly through the channel to pass through the perforate plate where it then diffuses over the entire upper portion of the chamber for return downwardly through the perforate plate and to the tubes to obtain the air balance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a partial plan view of a multi-zone dryer with parts shown broken away;

FIG. 1B is a continuation of FIG. 1A showing the right-hand part of the multi-zone dryer;

FIG. 2A is a vertical elevation of FIG. 1A;

FIG. 2B is a view in elevation of the structure shown in FIG. 18;

FIG. 3 is a vertical section on an enlarged scale taken through one drying section in a zone of the multi-zone dryer on an enlarged scale and taken generally along the line 3-3 of FIG. 1A; and

FIG. 4 is a vertical section taken generally along the line 4- 4 in FIG. 3.

the structure shown in BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1A, 18, 2A and 2B show the general configuration of a high velocity multi-zone heat transfer device and specifically a dryer for drying fragile tubular material such as collagen casing. The high velocity heated air provides rapid drying with the air impinging upon the tubular material and flowing relative thereto in a manner to avoid destruction of the tubular material. A single drying section of a zone of the multi-zone dryer is shown particularly in FIGS. 3 and 4 and the structure will be described followed by an overall description of the multi-zone dryer and the air supply and return paths to the individual drying sections of each zone.

A drying section as shown in FIGS. 3 and 4 is provided for handling four lengths of tubular material such as collagen or the like indicated generally at C which are continuously fed through the dryer. The drying section shown in FIGS. 3 and 4 comprises two identical subassemblies indicated generally at D-1 and D-2. Referring particularly to the subassembly D-2, there are a pair of side walls 10 and 11 extending the length of the drying section subassembly and fonning the side walls of the chamber with a bottom wall 12 spanning the side walls and having an air inlet 15 intermediate the ends thereof. A top wall 16 spans the distance between the side walls 10 and 11 to form a top for the chamber of the drying section. A pair of end bulkheads 17 and 18 close off the ends of the chamber and are in close fitting relation with the side wall, top wall and bottom wall to form a substantially air tight chamber. Each of these bulkheads has a central opening indicated at 19 and 20, respectively, to receive the ends of a tubular member 21 having a perforate wall permitting air flow therethrough. The air flow therethrough is shown by arrows in FIG. 4. The bulkheads 17 and 18 also have openings to receive the ends of a similar tubular member 22 laterally spaced from the tube 21. A threader tube 25 extends along the entire length of the dryer and in the space between the bulkheads. There is a downwardly extending U-shaped shroud 26 which is secured to upturned flanges of the tubular member 21 and which has perforations in its top horizontal surface adjacent the threader tube 25 to permit air to flow downwardly therepast. A similar threader tube 27 and shround 28 are associated with the tubular member 22.

Heated air at a high velocity enters the chamber through the inlet 15 in the bottom wall and impinges against a perforated bafile plate 30 extending across the width of the chamber and terminated short of the bulkheads l7 and 18, as shown in FIG. 3. As a result, the air is distributed substantially along the entire length of the lower part of the chamber. A portion of the air can rise up through an air guiding channel disposed between the perforate tubular members 21 and 22 and which extends along the length of the chamber between the bulkheads. This channel is defined by a pair of generally vertically extending plates 35 and 36 which are spaced apart from each other and which terminate at a level beneath the top of the tubular members 21 and 22 whereby some of the air emitted from the channel can move toward a perforate area of the tubes. The plates 35 and 36 each have a lower horizontally extending section 37 and 38, respectively, which are perforate for a part of their width and which are secured to the side walls and 11 of the chamber, respectivley, whereby air can pass through the perforations thereof to the openings in the lower part of the tubular members 21 and 22.

Approximately half of the air flowing upwardly in the air guiding channel is directed upwardly toward the top of the chamber, by a ratio of resistance between sections 37 and 38 and the channel, and through a horizontally disposed perforate plate 40 extending between the side walls 10 and 11 and the bulkheads 17 and 18 of the chamber. This plate is perforated over its entire area and spreads air to the edges and ends of the chamber whereby it can flow downwardly through plate perforations and to perforations in the upper parts of the tubular members 21 and 22. Some of the air flowing upwardly toward the perforate plate 40 is, in advance of said plate, converted from velocity to static pressure and thus flows more uniformly to and through the tubular members 21 and 22.

With the foregoing structure, air is caused to contact the tubular material C at a relatively high velocity without major impact thereon and about the entire periphery of the material and along the entire length which is in the drying section.

The flow of air in the drying section has minimal effect on the structure of the tubular material by having the air flow toward the tubular material along the entire length thereof as caused by the perforate tubular members and with air being exhausted from within the tubular members 21 and 22 from both ends thereof to balance forces on the material and minimize stretching. The air exhausting from the right-hand of the tubular member 21 as shown in FIG. 3 enters into an enclosed space having a top opening inspection door 50 and an exhaust port 51 communicating with the return duct 52. The left-hand end of the tubular member 21 communicates with a similar enclosed space having a top opening door 55 and an exhaust outlet 56 connecting to a return duct 57. Each of these return spaces also communicates with adjacent ends of the tubular member 22 and the ends of similar tubular members 60 and 61 of adjacent drying sections.

The subassembly D-l is of the same construction as subassembly D-2 and has tubular members 65 and 66 associated with the same structure as tubes 21 and 22 of assembly D-2. There may be as many subassemblies disposed side by side as desired for handling the desired number of tubular casings C at one time in the dryer.

The multi-zone nature of the dryer is shown in FIGS. 2A and 23 where three zones, namely zones 1, 2 and 3, are identified with the tubular casing C entering zone 1, passing to zone 2 and then zone 3 and then discharging from the dryer. The material contains the most moisture as it enters the dryer and is at a desired degree of dryness when it leaves the dryer. The air flow path beings with a motor driven blower 75 for zone 3 disposed above the drying sections as shown in FIGS. 1B and 2B and which receives air returning from zone 1 as well as a desired amount of fresh air. The air passes through a horizontal elevated duct 76 having suitable air heating elements disposed within a section 77 of the duct 76 and with the air then descending through a pair of vertical ducts 78 and 79 for connection to a pair of horizontal ducts extending beneath the drying sections corresponding to subassemblies D-1 and D-2 shown in FIG. 4, with the horizontal duct 80 supplying air to a series of drying sections corresponding to subassembly D-l. This duct has a number of upward branches 81-84 connecting to air inlets similar to the air inlet shown in FIGS. 3 and 4. A similar duct arrangement corresponding to duct 80 and branches 81- 84 is provided for supplying the row of drying sections corresponding to subassembly D-2. With this construction the entire number of drying sections of zones 3 are supplied with heated air at a relatively high velocity. The air is withdrawn from the spaces at the ends of the drying sections and from exhaust passages corresponding to passages 51 and 56 as shown in FIG. 3, through ducts which connect to a horizontally extending duct 90 at the rear of the drying sections which communicates with an upwardly inclined duct 91 extending to a horizontal duct section 92 which connects to the inlet side of a blower 93 disposed above the drying sections. The blower 93 for zone 2 has an outlet communicating with a pair of ducts 94 and 95 extending horizontally above the drying sections as shown in FIG. 1A which have a heater section 96 disposed therein for adding heat to the air and which communicate with a pair of downwardly extending ducts 97 and 98 which function similarly to the ducts 78 and 79 of zone 1 and provide the heated air to the drying sections of zone 2. One of the horizontal ducts 99 has branches 100, 101, 102 and 103 which supply air at a high velocity to the inlets corresponding to inlet 15 for the drying sections shown in FIGS. 3 and 4. A similar horizontal duct (not shown) supplies heated high velocity air to the adjacent drying section subassemblies.

Return air is exhausted from the drying sections of zone 2 similar to the manner in which the air exhausted from the drying sections of zone 3 with the return spaces at opposite ends of each drying sections connecting with a horizontal duct 105 which extends along the length of the drying sections of zone 2 and intermediate its ends connects with a vertical duct 106 which communicates with a horizontal duct 107 above the drying sections which extends to a heater 108 for adding heat to the air and with the outlet thereof communicating with a blower 109. The blower 109 for zone 1 has an outlet connecting to a downwardly extending duct 1 10 which supplies air to a horizontal duct 11 1 extending beneath the drying section subassemblies D-1 and D-2 of zone 1 of the dryer. This horizontal duct 111 has upward branches 112, 115, 117, 118, 119 and 120 communicating with inlet passages 15 of the drying section subassemblies D-1 and similar branches communicating with the inlets 15 of the drying section subassemblies D-2 whereby air can flow into the drying sections as shown by the arrows in FIG. 2A.

Return air from the drying sections of zone 1 moves downwardly through the return ports 51 and 56 as shown in FIG. 3, and then connects to a horizontal duct to the side of the drying sections and extending along the length of the zone and having a pair of upwardly extending ducts 126 and 127 which connect to an elevated horizontal return duct 128 which extends to an exhaust blower 130 (FIG. 1B). The outlet of this exhaust blower connects to a casing 131 having an upwardly extending vent 132 which can be opened when desired to vent some of the air carrying a substantial amount of moisture. The casing also has a second opening 133 which can be opened a desired amount to permit adding of fresh air to the circulating air system. The outlet of this casing 131 communicates with the inlet of the blower 75 for the drying sections of zone 3.

Although not intended as limiting the disclosure, certain examples may be given to illustrate a desired usage of a high velocity multi-zone dryer. Heated air can be delivered to each of the drying sections of zone 3 at the rate of 600 cubic feet per minute and with a tubular perforate member 21 of the drying section thereof having an approximate length of 3% feet and a diameter of approximately 3% inches, and there is a flow out of each end of the tubular member of approximately 300 cubic feet per minute. With an exit velocity of the air at each end of 4,000 feet per minute there is an air velocity through the tubular member perforations of approximately 2,500 feet per minute. In zone 1, each of the tubular members 21, 22 65 and 66 can have a length of approximately 2 feet and each is supplied with approximately 420 cubic feet per minute of air with half of this exhausting from each end of the tube at an exit velocity of 2,800 feet per minute. This provides an air velocity through the perforate wall of the tubular member of approximately 3,340 feet per minute.

I claim:

1. A heat transfer device for relatively fragile tubular material such as collagen or the like comprising, a chamber with a perforate tube disposed therein and with open ends of said tube opening outwardly of the chamber ends whereby the material can travel through the tube, an air inlet to said chamber intermediate the ends thereof, means for delivering air at a high velocity to said inlet, means for distributing air in said chamber to cause air to enter through the perforate tube entirely around and along the length of tubular material including a perforate plate extending for the entire length of the chamber at the side of the tube opposite the air inlet, and an air guiding channel spaced from said tube directing air upwardly through said perforate plate and partially shielding an adjacent section of the perforate tube, and an air return system connected to said tube open ends.

2. A heat transfer device as defined in claim 1 wherein said air distributing means includes a perforate baffle member in said chamber positioned in line with said air inlet.

3. A heat transfer device as defined in claim 1 wherein said air guiding channel includes a plate extending for the length of the chamber with a generally vertical portion defining part of said air channel and a generally horizontal portion spaced at a distance under said tube and having perforations to permit air flow therethrough.

4. A heat transfer device for fragile tubular material such as collagen or the like and having a plurality of treatment zones through which the material travels for progressive treatment thereof, each of said zones having a plurality of treatment sections with each section having a chamber with spaced-apart end bulkheads, a perforate tube in each chamber through which the material passes and having a diameter which is multiple of the diameter of the tubular material for direction air around the entire surface of the tubular material and with the ends of the tube opening through the bulkheads, an air inlet to each of said chambers intermediate the ends thereof, a perforate bafile opposite. each air inlet to break up the air flow and assist in directing air to the ends of the chamber, an air return connected to the ends of each of said tubes, and perforate plates positioned in each of said chambers to obtain air distribution along the entire length of the tubes and entirely therearound.

5. A heat transfer device as defined in claim 4 wherein there are a pair of tubes in each of said chambers with one of said perforate plates disposed horizontally thereabove and spanning the entire chamber and an air guiding channel along the length of each chamber directing air up through said horizontal perforate plate whereby said air can return through said horizontal perforate plate over the entire area thereof.

6. A heat transfer device for relatively fragile tubular material such as collagen or the like having a plurality of treatment sections with each section comprising; an enclosing chamber with end bulkheads, a pair of laterally spaced-apart tubes with perforated walls extending between bulkheads intermediate the top and bottom of the chamber and opening to the spaces beyond the bulkheads through which the material travels, an air inlet at the bottom of the chamber intermediate the bulkheads, a baffle across the inlet to break up the path of the entering air, means for supplying high velocity air to said air inlet, an air return connected to said spaces beyond the bulkheads whereby air leaves from both ends of the chamber to minimize the effect of air flow on the material, and means within said chamber to cause uniform air flow through the entire periphery of said tubes and along the entire length thereof to impinge air on the entire surface of the tubular materials in said chamber.

7. A heat transfer device as defined in claim 6 wherein said means causing uniform air flow comprises a first pair of plates extending between bulkheads and having opposed spacedapart generally vertical solid sections defining an upwardly extending air channel between tubes and generally horizontal sections under said tubes with parts thereof perforate to permit air flow to said tubes, and a horizontally disposed perforate plate spanning the entire chamber above said tubes and spaced from the upper end of said air channel whereby air flows beneath the horizontally disposed plate to said tubes and also upwardly along said air channel through the horizontally disposed perforate plate to the upper part of the chamber and is then spread over the entire area of the last mentioned plate for return flow therethrough downwardlyto said tubes.

8. A heat transfer device for relatively fragile tubular material such as collagen or the like comprising, a plurality of relatively short successive chambers with each chamber having a tube perforate over its entire length and circumference disposed therein and with open ends of said tube opening outwardly of the chamber ends whereby the material can travel through the tube, an air inlet to each of said chambers intermediate the ends thereof, means for delivering air at a high velocity to each of said inlets, means for distributing air in each of said chambers to cause air to enter through each of the perforate tubes entirely around and along the length of tubular material to have uniform balanced air impinge against said tubular material whereby said material can travel through the perforate tube without internal guiding supports, and an air return system connected to both open ends of the perforate tubes associated with the chambers to withdraw substantially equal amounts of air from both ends of the perforate tubes whereby the flow effects of the air tending to stretch the material are minimized. 

1. A heat transfer device for relatively fragile tubular material such as collagen or the like comprising, a chamber with a perforate tube disposed therein and with open ends of said tube opening outwardly of the chamber ends whereby the material can travel through the tube, an air inlet to said chamber intermediate the ends thereof, means for delivering air at a high velocity to said inlet, means for distributing air in said chamber to cause air to enter through the perforate tube entirely around and along the length of tubular material including a perforate plate extending for the entire length of the chamber at the side of the tube opposite the air inlet, and an air guiding channel spaced from said tube directing air upwardly through said perforate plate and partially shielding an adjacent section of the perforate tube, and an air return system connected to said tube open ends.
 2. A heat transfer device as defined in claim 1 wherein said air distributing means includes a perforate baffle member in said chamber positioned in line with said air inlet.
 3. A heat transfer device as defined in claim 1 wherein said air guiding channel includes a plate extending for the length of the chamber with a generally vertical portion defining part of said air channel and a generally horizontal portion spaced at a distance under said tube and having perforations to permit air flow therethrough.
 4. A heat transfer device for fragile tubular material such as collagen or the like and having a plurality of treatment zones through which the material travels for progressive treatment thereof, each of said zones having a plurality of treatment sections with each section having a chamber with spaced-apart end bulkheads, a perforate tube in each chamber through which the material passes and having a diameter which is multiple of the diameter of the tubular material for direction air around the entire surface of the tubular material and with the ends of the tube opening through the bulkheads, an air inlet to each of said chambers intermediate the ends thereof, a perforate baffle opposite each air inlet to break up the air flow and assist in directing air to the ends of the chamber, an air return connected to the ends of each of said tubes, and perforate plates positioned in each of said chambers to obtain air distribution alonG the entire length of the tubes and entirely therearound.
 5. A heat transfer device as defined in claim 4 wherein there are a pair of tubes in each of said chambers with one of said perforate plates disposed horizontally thereabove and spanning the entire chamber and an air guiding channel along the length of each chamber directing air up through said horizontal perforate plate whereby said air can return through said horizontal perforate plate over the entire area thereof.
 6. A heat transfer device for relatively fragile tubular material such as collagen or the like having a plurality of treatment sections with each section comprising; an enclosing chamber with end bulkheads, a pair of laterally spaced-apart tubes with perforated walls extending between bulkheads intermediate the top and bottom of the chamber and opening to the spaces beyond the bulkheads through which the material travels, an air inlet at the bottom of the chamber intermediate the bulkheads, a baffle across the inlet to break up the path of the entering air, means for supplying high velocity air to said air inlet, an air return connected to said spaces beyond the bulkheads whereby air leaves from both ends of the chamber to minimize the effect of air flow on the material, and means within said chamber to cause uniform air flow through the entire periphery of said tubes and along the entire length thereof to impinge air on the entire surface of the tubular materials in said chamber.
 7. A heat transfer device as defined in claim 6 wherein said means causing uniform air flow comprises a first pair of plates extending between bulkheads and having opposed spaced-apart generally vertical solid sections defining an upwardly extending air channel between tubes and generally horizontal sections under said tubes with parts thereof perforate to permit air flow to said tubes, and a horizontally disposed perforate plate spanning the entire chamber above said tubes and spaced from the upper end of said air channel whereby air flows beneath the horizontally disposed plate to said tubes and also upwardly along said air channel through the horizontally disposed perforate plate to the upper part of the chamber and is then spread over the entire area of the last mentioned plate for return flow therethrough downwardly to said tubes.
 8. A heat transfer device for relatively fragile tubular material such as collagen or the like comprising, a plurality of relatively short successive chambers with each chamber having a tube perforate over its entire length and circumference disposed therein and with open ends of said tube opening outwardly of the chamber ends whereby the material can travel through the tube, an air inlet to each of said chambers intermediate the ends thereof, means for delivering air at a high velocity to each of said inlets, means for distributing air in each of said chambers to cause air to enter through each of the perforate tubes entirely around and along the length of tubular material to have uniform balanced air impinge against said tubular material whereby said material can travel through the perforate tube without internal guiding supports, and an air return system connected to both open ends of the perforate tubes associated with the chambers to withdraw substantially equal amounts of air from both ends of the perforate tubes whereby the flow effects of the air tending to stretch the material are minimized. 